Fear can sometimes be a useful emotion. For instance, let's say you're an astronaut on the moon and you fear that your partner has been turned into Dracula. The next time he goes out for the moon pieces, wham! You just slam the door behind him and blast off. He might call you on the radio and say he's not Dracula, but you just say, "Think again, bat man."

Some say Sherlock Holmes' regular use of cocaine was Doyle's vehicle to illustrate the character's moral weakness. It likely began more simply as a window into the culture of the time, when hard stimulants weren't the taboo they are today. W.H. Auden apparently did believe his own dependence on the stimulant Benzedrine to be a sign of weak character, but he still took it every working morning and endorsed its creative influences effusively. Jack Kerouac and Jean-Paul Sartre offer similar testaments. Sir Elton John sang "Bennie and the Jets" ... which may be in praise of Benzedrine, but is open to interpretation, depending where you stand on mohair suits.

2013's cultural Benzedrines are Adderall (a brand name for amphetamine) and excessive coffee. Caffeine remains non-prescription legal, and it's still universally considered benignly delightful to make offhand comments about how unproductive we are without it. "I'm a total grump if I don't get my coffee!" Funny, relatable, true. "Get out of my way when I haven't had my coffee -- or I will hurt you." Consider the ice broken. "Seriously I will cut you." Okay, that's enough.

"What is the frequency, Kenneth? Is this your Benzedrine? Kenneth? Kenneth, look at me."

Despite its legality and social acceptance, people dependent on caffeine do occasionally betray a tenor of insecurity about it. There's an element of fear. That may be why we laugh about it. I see it in the retiring eyes of people asking me about their caffeine habits, and in the numbers of people who read and share stories we publish about coffee. A cover article titled "Is Caffeine Killing You?" would, almost regardless of its execution, probably be the most popular thing on this site. Ninety percent of people in the U.S. ingest caffeine on a daily basis, and many of them also fear death.

Meanwhile, for some, a threat to creativity is only slightly less terrifying than a threat to life. Being boring is just a notch above being malicious or genocidal in the hierarchy of human values for generation Millennial. So when, last week, friend-of-The-AtlanticMaria Konnikova wrote an interesting piece for The New Yorker entitled "How Caffeine Can Cramp Creativity," it concerned people like me. That is, people who use caffeine regularly and also sometimes want to create things and be interesting. The article read, "While caffeine has numerous benefits, it appears that the drug may undermine creativity more than it stimulates it." So let's look at caffeine biochemistry for a quick second.

(picturezealot/flickr)

The basic science of caffeine goes something like this. Cyclic AMP gives your body energy. Phosphodiesterase is an enzyme that breaks down cyclic AMP. Caffeine blocks phosphodiesterase. So cyclic AMP stays around longer when you have caffeine in your blood, and you have more energy. It comes from the natural substances that your body produces and always give you energy; they just last longer.

Caffeine also blocks adenosine receptors in your brain. Stephen Braun, author of Buzz: The Science and Lore of Alcohol and Caffeine, once explained it as an "indirect stimulant, as opposed to, say, amphetamine which liberates dopamine, a directly stimulating neurotransmitter. By blocking adenosine receptors, caffeine allows the brain's own stimulating neurotransmitters (i.e. glutamate and dopamine) to do their thing with greater gusto and less restraint."

I like the analogy that it turns off the body's brakes. How it affects creativity is mostly conjecture, and will vary from person to person. To say that it cramps creativity is kind of at best an interesting potential notion. It's one that begins with what is a very real and common complaint among creatives who take hard stimulants like Adderall: that it makes them too focused. The medication makes minutiae deeply stimulating, fascinating. People can get hung up for 45 minutes on what pair of pants to wear -- because, have you felt corduroy? -- to the point they're late to work. At least they did get the right pants.

Prescription stimulants are what enable hyperactive people to spend 12 hours memorizing organic chemistry equations. The brain is getting a natural dose of the stimulation that it might otherwise get from checking Twitter or email or taking a break to eat scones. That stuff doesn't matter anymore. It's the extreme version of what makes meth addicts spend 12 hours digging at an itchy scab on their face. Such an interesting scab, and so important to keep picking at it. It is the state of mind of a worker bee, not an out-of-the-box creative.

The problem with this degree of focus, as Jonah Lehrer would tell us, is that moments of insight and genius come in the shower, on walks, doing hot yoga; when the mind is less focused and allowed to wander. Konnikova makes the same point: "Creative insights and imaginative solutions often occur when we stop working on a particular problem and let our mind move on to something unrelated." Overstimulated, the wandering mind's creative potential could theoretically be diminished.

As someone who works with a lot of self-described creative types, my experience is that the most common barriers to creating are initiative, commitment, and self-doubt. Caffeine helps with all three of those. Even if there is some sort of subtle effect on free-association or Rorschach inkblots, or some people overdo it and lose sight of the big picture in a euphoric state of hyper-vigilance, I can't see that outweighing the benefits of stimulation, disinhibition, and improved ability to focus on work. Deferring to Woody Allen: "80 percent of success is showing up."

How all of this comes together to make any one of us think differently varies, of course. Case studies for caffeine endorsement abound: Simone de Beauvoir, Beethoven, Gustav Mahler, and the famous example Honoré de Balzac, who "is said to have" had 50 cups most days. He was plenty creative, but was also a notoriously eccentric man with gastric problems who died at 51 of a cardiac issue.

Keep trying until you solve the case, because this is important.

If you're taking in enough caffeine that it messes with your sleep, the benefit can definitely be negated. If you become so motivated and vigilant that you spend hours perfecting every aspect of basic tasks, neglecting others, or your own relationships or hygiene, or not exercising, all of that is also no good. Like every drug, its effects can't be considered in a vacuum. Like all good things, moderation. You can't get too much moderation. "Fear can sometimes be a useful emotion."

Auden's best work came out of his Benzedrine period, but few who take hard stimulants become Auden. Adderall and caffeine likewise focus the minds of different people in different ways. A nice thing about caffeine, though, is you can legally experiment with it on yourself and your friends. If you don't have any precluding medical conditions, take a Red Bull or Full Throttle or Neurogasm or two, and then try to be creative. For example, name as many hypothetical new energy drinks as you can in, say, 14 minutes. Then test yourself sober. Another good prompt might be, why did 25,000 bumble bees die last week in a Target parking lot? Be creative. Think of as many answers as you can.

If you feel your heart beating irregularly or stopping or your eyes twitching, that was probably too much caffeine. The same goes if you only came up with one extremely elaborate answer. (Probably do get in touch with the environmental detectives on the bee case, though. Did you solve it? Keep trying until you do, because this is important.)

For most of us, expect caffeine to show some improvement in productivity on creative tasks. Of course like we've seen before ("How much caffeine before you should go to the E.R.?"), keep in mind that caffeine sends people to the hospital all the time. It's a drug: moderation, useful fear, respect. The new DSM does include caffeine intoxication and withdrawal as psychiatric disorders, when they're bad enough to impair our day-to-day functioning. But outside of impairment-level usage, including the sort of intoxication that might mimic the hyper-focused stimulation of taking amphetamines, we really don't have evidence that it undermines creativity.